In my experience, yes you always get refills on soft drinks at table service meals. Counter Service is a little different though. I am pretty sure you don't get refills on counter service drinks. At least the lines are always so long that I have never gone back up and asked for one. Also, some places will give you a large drink with a counter service and some will only let you have a medium. Some would normally give you a medium, but if you ask they'll give you large. There is no rhyme or reason to this I don't think, must just depend on the cast member.